Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935905Ab2JaSVj (ORCPT ); Wed, 31 Oct 2012 14:21:39 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:35779 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935867Ab2JaSVf (ORCPT ); Wed, 31 Oct 2012 14:21:35 -0400 Date: Wed, 31 Oct 2012 11:21:32 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Wen Congyang cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, Rob Landley , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , Yinghai Lu , "rusty@rustcorp.com.au" Subject: Re: [PART6 Patch] mempolicy: fix is_valid_nodemask() In-Reply-To: <1351675458-11859-2-git-send-email-wency@cn.fujitsu.com> Message-ID: References: <1351675458-11859-1-git-send-email-wency@cn.fujitsu.com> <1351675458-11859-2-git-send-email-wency@cn.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1343 Lines: 28 On Wed, 31 Oct 2012, Wen Congyang wrote: > From: Lai Jiangshan > > is_valid_nodemask() is introduced by 19770b32. but it does not match > its comments, because it does not check the zone which > policy_zone. > > Also in b377fd, this commits told us, if highest zone is ZONE_MOVABLE, > we should also apply memory policies to it. so ZONE_MOVABLE should be valid zone > for policies. is_valid_nodemask() need to be changed to match it. > > Fix: check all zones, even its zoneid > policy_zone. > Use nodes_intersects() instead open code to check it. > This changes the semantics of MPOL_BIND to be considerably different than what it is today: slab allocations are no longer bound by such a policy which isn't consistent with what userspace expects or is specified by set_mempolicy() and there's no way, with your patch, to actually specify that we don't care about ZONE_MOVABLE and that the slab allocations _should_ actually be allocated on movable-only zones. You have to respect cases where people aren't interested in node hotplug and not cause a regression. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/